1. Field of the Invention
The present invention relates to manual winches with knockout tension release mechanisms, more particularly, the present invention relates to manual marine winches with safety knockout override preventing release of winch tension without the handle in the stowed position.
2. Background Information
General Manual Marine Winches
Winches have been used in many applications. The present invention relates to manual winches which have been widely used in barges, tow boats and the like. Typically such a manual winch is attached to a boat deck and spools a towing cable or winch line on a rotating drum.
Manual winches remain in common use where a powered winch would be impractical or inefficient. In a manual winch the operator, through various mechanical advantages, can generate a very large tension on the winch line. Examples of manual winches are described in greater detail in U.S. Pat. No. 5,947,450 which is incorporated herein by reference. Examples of manual winches are sold by W. W. Patterson Company, Nabrico and Nashville Bridge Company. Other representative examples are found in U.S. Pat. Nos. 4,106,754; 4,456,227; 4,566,674; 6,431,525; 6,572,083; 6,726,182; 6,938,881; 7,128,307; 7,179,852; 7,686,282, which are incorporated herein by reference.
A background summary of conventional winch design may be helpful to fully understand the scope and operation of the present invention.
The conventional prior art manual marine winch 10, similar to manual winches which are described in U.S. Pat. No. 5,947,450, is shown in FIG. 1 and includes a base plate 12 and a pair of spaced side plates 14 surrounding a rotatable spool or drum assembly. The rotatable spool assembly is rotationally supported between the side plates 14 and includes a drum 16, a protecting flange on one side of the drum 16 and a controlling gear 20 on the other side of the drum 16. A control assembly is supported by the side plates 14 and engages with the gear 20 to rotate the drum 16 for spooling of a cable (not shown) or wire rope or winch line thereon. The control assembly extends through one side plate 14. The control assembly includes a hand wheel 24 and an actuating lever or handle 26, also called a ratchet handle 26, each of which are used for manually operating the winch 10.
The ratchet handle 26 will typically have a stowed position, generally the rearward position, in which it is disengaged from the gearing associated with the drum 16. The stowed position may have a stop secured to the sidewall or side plate 14 acting as a rest for the handle 26 and a visual indicator that the handle is in the stowed position. As the handle 26 is rotated away from the stowed position it will engage the gearing associated with the drum to allow for tensioning of the drum and associated winch line, in a conventional fashion known in the art.
A foot brake 28 may be attached to the side plate 14 through which the control assembly extends. The foot brake 28 is adapted to frictionally engage the hand wheel 24. A swivel link 30 may be attached to the base plate 12 at a rear of the winch 10 and pivotally attaches the winch 10 to a D-ring 32 of a boat deck or the like. A step or foot 34 is attached to the underside of the base plate 12 near a forward portion of the winch 10. A gear guard 36 is attached to one of the side plates 14 on the same side as the gear 20 and is positioned in a cutout formed in the side plate 14. The gear guard 36 prevents the cable from interfering with or becoming wrapped behind the gear 20. Similarly, a flange guard is attached to the other side plate 14 in a cutout formed therein. The flange guard prevents the cable from being wrapped behind the flange.
The construction of the manual swivel winch 10 may include the use of four tubular spacers (not shown) for spacing the side plates 14 apart. A bolt 40 extends through the center of each spacer through aligned holes in the opposed side plates 14 and is secured by nuts 42.
In a conventional marine winch a wire rope, the winch line, is spooled back and forth around the rotating drum and the winch line is subject to very large loads. The high loading can cause the outer layers of wire rope to become fouled, jammed or begin binding within the spaces between the lower level wire ropes. Further, rapid tension release in existing wire rope winch systems can result in what is known as “bird-nesting” of the spooled wire rope. This can make unwinding the winch very difficult in subsequent operation, and often requires a second deck hand to assist in the unwinding of the wire rope, or even the engine power of the tow boat. U.S. Pat. No. 7,543,800 which is incorporated herein by reference addressed some of these problems with the design and implementation of a “single stack” winch.
A single stack winch 50 as described in U.S. Pat. No. 7,543,800, which is incorporated herein by reference, is disclosed in FIG. 2 which illustrates a winch 50 that includes a pair of spaced side plates 54 defining an open bottom. A rotating spool or drum assembly is supported between the side plates 54 and includes drum 56 with a protecting flange 58 on one side of the drum 56 and a controlling drum gear 60 on the other side of the drum 56. The construction of the spool or drum assembly is a key feature of the single stack winch 50 design. Adjacent the drum gear 60 is a stacking flange which is spaced from the drum gear 60 a distance sufficient to receive a single width of winch line. The winch 50 includes stacking area fender 70 as a protective fender and a protective plate 72 with rope access slot 74 further protecting the stacking space and a spacer or support 90.
The U.S. Pat. No. 7,543,800 further notes that the remaining elements of the winch 50 are conventional and known to those in the art. For example the winch includes a hand wheel 76 and lever tension mechanism, also known as a ratchet handle 78 is used to rotate the drum gear 60 through gearing 80 in a conventional fashion. The ratchet handle 78 will typically have a stowed position, generally the rearward position, in which it is disengaged from the gearing associated with the drum 16, but as the ratchet handle 78 is rotated it will engage the gearing associated with the drum to allow for tensioning of the drum and associated winch line.
The tension is held on ratchet gears 82 that are engaged with pawls 84. In conventional tensioning operation for the winch 50 the pawls 84 are engaged with the ratchet gears 82 and the operator will rapidly wind up the winch line, and increase the tension, initially through the operation of the hand wheel 76. Once the tension reaches a relatively high amount on the winch line, the operator will continue the tensioning through the repeated use of the ratchet handle 78, often with the use of a handle extension or a “cheater bar” to add increased leverage. Once the final tension is achieved it is intended for the operator to move the handle to the disengaged or stowed position, typically the rearward position, to prepare the winch for tension release when desired.
A knockout lever 86, also known in the art, is used to disengage the pawls 84 from the gears 82 to release tension on the winch 50, when desired. When controlled payout is desired the footbrake is engaged and the knockout lever 86 is utilized to disengage the pawls 84 from the gears 82 to allow for slow payout. Often the tension release is allowed to be somewhat rapid. The knockout lever 86 is so named as it is often struck to be knocked out of engagement.
Unintentional Handle Rotation with Knockout Operation
The manual tensioning handles of known marine winches, such as handles 26 and 78 of the winches 10 and 50 of FIGS. 1 and 2, respectively, should be disengaged to allow for safe unloading or payout of the winch line. If the tension is released on the drum through a knockout device, such as lever 86, with the handles 26 or 78 still accidentally engaged, the handles naturally will rotate, through the gearing, with the drum. In such a case, with the drum under high loads or tension, the accidentally drum-engaged handles can be rotated quite fast and violently before striking a rear stop or the ship's deck. Aside to damaging the handles in this movement, of far greater concern is the potential injury to workers around the winch during such accidental winch handle movement.
The danger of unintended handle movement is only heightened if a handle extension, also called a cheater bar, is left on the handle that is left engaged with the gearing. A cheater bar is merely a length of pipe that operators have been known to add to the manual marine winch handle to increase the effective lever arm available to the operator for ease of tensioning the winch 10 or 50. Operators have broken arms and legs due to such undesired violent handle and cheater bar motion during knockout operation.
U.S. Patent Application Publication No. 2012-0068132, which is incorporated herein by reference, provides one solution to this handle problem with the design of a manual marine winch that includes a self releasing handle. The handle includes i) a ratchet gear coupled to the drum wherein rotation of the ratchet gear will cause rotation of the drum, ii) a rotating handle body with a manual end grip, iii) a user engaged trigger mechanism on the end grip moveable between an engaged position and a release position, and iv) a handle locking pawl on the handle body and coupled to the trigger mechanism and moveable between a position engaged with the ratchet gear rotationally securing the handle body to the ratchet gear and the drum when the trigger is in the engaged position and a position disengaged with the ratchet gear rotationally separating the handle body from the ratchet gear and the drum when the trigger is not in the engaged position.
The self releasing handle represents a relatively complex handle and may not be adopted by all winch users. Thus there remains a need for preventing undesired handle movement during tension release on manual marine winches with the operation of a knockout device.
It is an object of the present invention to minimize the drawbacks of the existing manual winch handles and to provide a simple easy and safe marine winch.